The present invention relates to an ultrasound probe which, in use, is inserted into a human body cavity through the endovagine, intestinum rectum, etc.
Currently, the ultrasound diagnosis, being compared to an X-ray computer tomography apparatus, magnetic resonance imaging (MRI) apparatus, gamma camera, etc., is excellent in terms of real time, compact, cost and safety aspects and indispensable in a medical field, in particular, a urology and gynecology. The pulse echo method constitutes one of its main stream. This method is excellent in a distance resolution and enables a cross-sectional structure of a living body to be converted to a visual image.
As well known in the art, however, this method imparts a restriction to the absorption of an ultrasound energy by the living body, its boundary and attenuation wave as well as to its reaching distance. Further, the frame rate has its lower limit set so as to visualize a motion smoothly. These impart a limitation to the depth of a visual field on diagnosis. In order to clearly visualize a deep-seated object of a living body, such as a fetus or prostate gland, the ultrasound probe has been developed and intensively used which is inserted into the living body through the endovagine, rectal, etc., route.
This type of probe has a structure comprising a substantially cylindrical, easier-to-grip part 3 of a proper thickness and a narrow-rod-like insertion part 2 extending from the grip part 3 to ensure ready insertion into the body cavity. A piezoelectric element array 1 is provided at a forward end portion of the insertion part. The grip section 3 has its upper side somewhat cut to provide a flat section 5, so that the operator can grasp the upper and lower sides of the grip section without being so recognized. The probe is carefully water-proofed and formed with a minimal uneven surface to ensure its ready washing and sterilization.
For prostate diagnosis it is probed effective to actually check a sampled tissue. For this reason, the coelom probe has a hook-shaped hole 7 and circular recess 9 so as to allow a centesis adaptor to be mounted thereon as shown in FIG. 2. In order to mount a centesis adaptor on the coelom probe, a hook 8 on the forward end portion of a sheath tube 6 set on a clamp 10 of the centesis adaptor is latched to the hook-shaped hole 9 of the probe and a tight clamp is made with a screw 11 attached to the recess 9.
The operator aims a centesis needle at a target, while looking at an ultrasound image, stabs the needle into the target organ and pulls it back. By doing so, the tissue sample is scraped off the organ in a manner to be deposited within the hook of the forward end portion of the needle.
This type of adaptor is complicated in construction and very difficult to wash and sterilize and sometimes provides an obstacle in a centesis operation. Further, if the centesis adaptor is repeatedly attached and detached to and from the probe, then the recess 9 is worn away, sometimes failing to adequately fix the centesis adaptor to the probe. The serious defect is in that, since some force is needed at each push-out, stabbing and pull-back action, the probe is somewhat shacken, so that the centesis needle is displaced off the target.
In recent years, a centesis instrument (hereinafter referred to as a "Bird Gun"), manufactured by Bird Co, Ltd, has been rapidly accepted in this field. This Bird Gun has a body of a substantially hexagonal prism. A spring and mechanism in this body are so constructed that a centesis needle can be rapidly and forcibly pushed out from the Gun's body and rapidly pulled back from a location where the needle is fully extended out. This increases a probability that this rapid action will ensure accurate stabbing of the needle into a target organ in comparison with a slot manual motion.
The Bird Gun is set to the probe in the following step sequence.
(1) The spring is adequately stretched taut and locked. PA0 (2) The centesis needle somewhat projected from the body is passed through the sheath tube 6 of the centesis adaptor. PA0 (3) The Gun's body is placed on the flat section 5 of the grip section 3 of the probe. PA0 (1) The operator grips the Bird Gun's body and probe by his or her own hands. PA0 (2) The sheath tube, together with the probe's insertion section, is inserted, for example, into the intestinum rectum. PA0 (3) A target is set while looking at an ultrasound image. PA0 (4) A sight of the Bird Gun at a target is adjusted. PA0 (5) A trigger button of the Bird Gun is depressed. PA0 (6) The locking of the spring is released to allow a tissue sample to be scraped off.
The stabbing step sequence is as follows:
Here, the problem with this sequence is that it is difficult for the operator to stably grip the Bird Gun's body, together with the probe, even with both his or her hands. That is, the Bird Gun's body (hexagonal prism) is narrow and not flat and unsteady on the flat section of the probe. Therefore, there is the inconvenience of having to readjust the sighting of the Bird Gun and, in addition, there is also a risk that a stabbing operation will be shifted off the target.
Further, since the operator's hands are gripping the Bird Gun's body and probe, it has not been possible to perform even the simple operation of, for example, depressing an image freeze button.